The 2016 Birthstone Update: Spinel Joins August
The 2016 Birthstone Update: Spinel Joins August
The first joint revision to the modern American birthstone list in fourteen years
In 2016, the American Gem Trade Association (AGTA) and Jewelers of America (JA) jointly announced the addition of spinel as an official August birthstone — the first collaborative revision to the modern American birthstone list since the addition of tanzanite to December in 2002. The update elevated August to a three-stone month, with spinel joining the long-established alternatives of peridot and sardonyx.
Background: The Modern Birthstone List
The standardised American birthstone list traces its origins to a 1912 agreement among jewellery trade organisations, later revised in 1952 and again in 2002. The list is not a statutory document but rather a trade consensus that carries significant commercial and cultural weight, shaping consumer expectations, retail merchandising, and jewellery gifting traditions across North America and beyond. Any amendment requires broad industry agreement, which explains why revisions have been infrequent.
Why Spinel
The case for spinel rested on several well-documented grounds. First, its gemological credentials are unimpeachable: spinel (MgAl₂O₄) crystallises in the cubic system, achieves a Mohs hardness of 8, and exhibits good to excellent toughness with no cleavage — properties that make it eminently suitable for everyday jewellery wear. Second, spinel occurs in an exceptionally broad colour range, including vivid reds, saturated pinks, bright oranges, blues, and near-colourless stones, offering consumers genuine variety within a single species. Third, and perhaps most compelling to a trade increasingly attentive to disclosure, gem-quality spinel is one of the few commercially significant coloured stones that is routinely sold without heat treatment or other enhancement. This freedom from routine treatment was explicitly cited as a factor in the designation, distinguishing spinel in a market where treated stones are the norm.
Historically, spinel's credentials are formidable. Many of the most celebrated "rubies" in royal and imperial collections — including the Timur Ruby in the British Crown Jewels and the Black Prince's Ruby set in the Imperial State Crown — are in fact large red spinels. The gem's long confusion with ruby, resolved only by modern mineralogy, paradoxically lent it a certain prestige once the distinction became widely understood.
Market Context
By the early 2010s, spinel had undergone a marked reassessment in the fine-gemstone trade. Vivid red and hot-pink spinels from Mahenge, Tanzania, and from the Mogok Valley of Myanmar commanded rising prices at auction and attracted serious collector interest. The AGTA and JA designation formalised what the trade had already begun to recognise: that spinel was no longer a footnote to ruby but a desirable gem in its own right. Birthstone status, while primarily a retail and gifting driver, also introduces a species to a far broader consumer audience than collector markets alone can reach.
August's Three-Stone Status
August now shares with a small number of months the distinction of offering three recognised alternatives. Peridot, the yellow-green olivine variety long associated with August, retains its position as the most widely recognised August stone. Sardonyx, a banded variety of onyx with reddish-brown and white layers, remains from the original 1912 list. Spinel's addition gives the month an option that spans nearly the full colour spectrum and sits comfortably at the finer end of the market — a complement rather than a competitor to peridot's distinctive colour identity.